result_map_or_into_option: add good and bad examples

Author: nickrtorres

clippy_lints/src/methods/mod.rs

@@ -340,8 +340,13 @@ declare_clippy_lint! {
     ///
     /// **Example:**
     /// ```rust
-    /// # let opt = Some(1);
-    /// # let r = opt.map_or(None, Some);
+    /// # Bad
+    /// let r: Result<u32, &str> = Ok(1);
+    /// assert_eq!(Some(1), r.map_or(None, Some));
+    ///
+    /// # Good
+    /// let r: Result<u32, &str> = Ok(1);
+    /// assert_eq!(Some(1), r.ok());
     /// ```
     pub RESULT_MAP_OR_INTO_OPTION,
     style,